| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit which is restrained from being increased in number of parts, comparatively simple in structure, capable of dissipating heat generated by a switching device, and reducing a circuit pattern in electric resistance. SOLUTION: An electric component 13 is provided on either or both surfaces of a board 12 formed of insulating material, and switching devices 16 and 17 are included in the electric component 13. A circuit pattern 14 is formed on both surfaces of the board 12, and the circuit patterns 14 are electrically connected to the electric component 13 through the intermediary of through-holes 12a penetrating through the board 12. A distance between the switching devices is set as long as 1 cm or above. Provided that the exposed area of both surfaces of the board after electric component is arranged is represented by 100%, a circuit pattern is formed on both the exposed surfaces of the board so as to make its surface area equal to 40% or above.
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